Doors, especially those which are solid-core or simply made from a hard wood such as oak, can be quite heavy and unwieldy to move and install, despite having holes pre-punched and mortised for a knob and hinges, respectively. The solid-core, hollow metal, and inlaid-glass doors so often installed in today's commercial, medical, government, and educational facilities are difficult for one or even two people to move, much less hang and install. Application of the requisite hinges to these types of doors is also problematic.
Previously, installation of a new commercial door, which may have a weight that exceeds one hundred pounds, required using a two-wheel cart or dolly, possibly one which was intended for drywall or was homemade. Yet a door placed on such a cart is apt to wobble and will hang off of one end, striking and dragging on the ground. Added difficulty lies in having to balance the door when moving it with a prior art contraption. Because protecting a new door from scratches is one of the utmost concerns, it is not feasible to haphazardly weld guides and/or a shaft to an existing hand cart for door transport.
Hinges are not usually installed on doors at the time of manufacture, so to attach them to doors has required a separate, horizontally-oriented device incorporating a system of supports and/or wedges. Once a hinge plate is attached to a door, the door must be placed back on a vertically-oriented, two-wheeled cart and awkwardly pushed to a door frame for final installation. There, the installer must carefully align the hinges with the door jamb.
Considerable problems can arise at this point in the door installation process: the installer must let go of the door when reaching for the necessary tools, though no screw connects it to the jamb at that point. Leaving, even if only temporarily, a heavy door precariously retained by an unscrewed top hinge set in its corresponding jamb pocket involves a significant risk of injury. A strong wind or even inadvertent slight contact can be enough to cause the door to fall. Accordingly, two or more people are often needed to install a door.
Challenges also exist when repairing or replacing a door. Often, a door frame will have come from the same manufacturer that made the door. Hinge placement, though, can vary from manufacturer to manufacturer. Thus, when attempting to install or repair a new door in an old frame, the installer must, for extended periods of time, direct his or her attention from preventing the door from falling, or at least getting scratched, and focus on measuring and double-checking to ensure that the door's hinges will precisely engage the pockets in the jamb, which may have been produced by a different manufacturer from that of the door.